Method and apparatus for submarine signaling.



H. A. FESSENDEN.

METHOD AND APPARATUS FOR SUBMARINE SIGNALING. APPLICATION FILED JAN.29.I913.

v 2@7,388. Patented Dec. 5,1916.

o o a o o o o o a o o o o o a u a o o o o e a 5. III/I/I/I/IIIIIIII/\X/ITHESEIES:

UNITED STATES PATENT curios.

REGINALD A. FESSENDEN, OF BROOKLINE, MASSACHUSETTS, ASSIGNOR TOS'UBMARINE SIGNAL COMPANY, OF WATERVILLE, 1VIAI1\TE, A CORPORATION OFMAINE.

METHOD AND APPARATUS FOR SUBMARINE SIGNALING.

memes.

Specification of Letters Patent.

Patented Dec. 5, 1916.

Application filed January 29, 1913. Serial No. 744,793.

0 all Whom it may concern Be it known that I, REGINALD A. FESSEN- DEN,of Brookline, in the county of Norfolk and State of Massachusetts, acitizen of the United States, have invented certain new and usefulImprovements in Methods and Apparatus for Submarine Signaling, of whichthe following is a specification. The invention described herein relatesto elect'rodynamic apparatus and methods, for the receipt of energy, andmore particularly to submarine signaling.

It has for its object increased efficiency in these lines and moreparticularly the more efficient transmission and receipt of submarinesignals.

The invention is hereinafter more fully described and claimed. I

In the accompanying drawings Figure 1 illustrates diagrammaticallyreceiving circuits arranged to embody my invention. Figs. 2 and 3 showdiagrammatically apparatus for use as a receiving transmitter.

In Fig. 1, 11 represents the skin of a ship. In place of this may beused a diaphragm inserted in a hole cut in the side of the ship,

or a diaphragm attached to-the side ofthe ship, preferably to theinside, the space between the diaphragm and the side of the ship beingfilled with water or other liquid, as oil, which may be under pressure.Or,

instead of liquid, compressed gas may be used, as air or carbonic acid.In the figure, 35 1s such a diaphragm, attached to the inside of theskin 11 of the ship, 36 being the liquid, and 37, 37 a packing ring,preferably of rubber. The diaphragm may be so constructed that whenstruck it vibrates forsome tlme, llke a tuning fork, or which may bedead-beat.

The apparatus 12, mounted on the skin of the ship 11 is preferably ofthe character shown in detail in Fig. 2, and described below. It formsthe subject-matter of Letters Patent No. 1,167,366, dated January 4, 1916, divided out from this case. When it is used and the switch 13 isthrown down, and the key 16 depressed (moved to the right), current fromthe alternating current dynamo or source of intermittent current 15flows into 12 and causes the tube 40 of Fig. 2 to vibrate with greatforce, say, in an appara tus of given size, with over 3500 lbs. stress.This tube being attached to the skin of the ship directly or indirectlyas in the case where it is mounted on the diaphragm 35, or attached to arod or spring, produces compressional waves in the water outside of theships skin, analogous to sound waves in air, which waves are transmittedand received at the receiving station. The frequency of the waves sotransmitted may be any desired, ranging from 5 per second to severalthousand per second. In practice the frequency is preferably determinedby the frequency of the source 15. The key 16 may be used fortelegraphing, as in the case of the ordinary telegraph. When the switch13 is thrown up, the device 12 is put in cir-. cuit with the battery 38and the controlling device 14, which may be a carbon telephonetransmitter where large currents are used or a transmitter and relay.Telephonic transmission through the water is accomplished by talkinginto the transmitter 14.

\Vhen the switch 13 is thrown down and the switch 17 up, and the key 16is up (moved to the left) the device 12 is connected to the station, thewaves cause the skin of the ship to move, carrying with it the tube 40(Fig.

2), and the motion of 40 causes currents to be generated in the windlng46, 47 (Fig. 2)

' which currents actuate the receivers 27, 28.

The current entering at the righthand side of the switch 17 andconductor 21, divides, one part flowing through the differentialtransformer primary 22, the variable induc-, tance 29, 29 and thenuniting with the other half which has flowed through the other primary23 and the fixed inductance 31, 31 both then flowing back to the otherside of the switch 17 through the conductor 33. The adjustableinductance 29, 29 has preferablv a condenser, fixed or variable, 30inserted in series with it and preferably between the two elements 29,29 In case the condenser 30 is variable the inductance 29, 29 may befixed. When the circuit is derived from a battery or other continuouscurrent source the inductance 31, 31 has no capacity in series with it.This type of. apparatus is hence sharply divided from all previous kindsin that the two sides are dissimilar, one being tuned to a givenfrequency by means of varying 30 or 29, 29 while the other side isuntuned, i. 6., non

resonant.

each other.

The inductances 29, 29 and 31,- 31 are preferably constructed in twoparts, each inductance consisting of a pair of arms. In like manner thetransformer 23, 25, 24, 22 consists of two twin insulated wire Windings,one wire of each twin winding being a primary coil as 22, the other asecondary as 24. The twoparts are preferably assembled so as to toucheach other physically, and thus secure greater efficiency of operation,and so as to assist or oppose each other as may be found best, butpreferably so that the primaries oppose each other. This is determinedby varying the connections and using that connection which is found tobe the most effective for the particular case, for example, byinterchanging the terminals of with each other or interchanging theterminals of any of the other coils with each other, for example, thoseof the coils 23, 24, o

22, 31, 31 29, 29 until the best result is obtained. The secondariesalso are preferably connected so that they are in series with each otherand so add their voltages, impressed upon them by the primaries, but sothat their mutual inductive effects on each other are opposed, i. 6., sothat the inductance of'the two secondaries 24, 25, in series is lessthan the sum of the inductance of24 plus the inductance of 25 when thetwo secondaries are removed to a distance from I have found that thisgives better elimination of extraneous noises. The transformer, thefixed inductance and the variable inductance are preferably arranged onplanes at right angles to each other. If

the condenser is adjustable, a number of sections are preferably made,having the ratios 1, 3, 5, 7, 9, 11, etc., and arranged so as to bethrown in parallel by a spiral cut contact As the sum of l and 3 is 2squared, and the sum of 1, 3 and 5 is 3 squared, etc., and as the wavelength is as the square root of thecapacity, a dial may be attached tothe spiral cut contact to operate it by hand in such a Way that thefirst position will. give a wave length of 1 foot, the second positionwill give two feet,-etc., i. e. the spacing on the dial will correspondexactly to the wave length and indicate the adjustment. The samearrangement can be made for the inductance, if desired, but here thecontactsmay be in series instead of in parallel. .If both are soarranged the Wave length is found by multiplying the reading on thecondenser dial by that on the inductance dial. The receivers 27, 28 areconnected in series with the secondaries 24, 25. A condenser 26 whichmay be adjustable, may also be inserted in series, but is preferablyomitted for most work.

In the operation of this device, the currents generated by the signalsto be detogether through 21. The adjustable inductance 29, 29 beingadjusted so that that side of the branch circuit is tuned to the signalsto be received, say 1,000 per second, the currents from the signals tobereceived fiow almost entirely through. that branch and very littlethrough the branch containing 31, 31 Consequently the primary 22produces a strong effect in the secondary circuit 24, 25, 27, 28. On theother hand, the extraneous disturbance currents flow approximatelyequally through the two branches, and so the effect of 22 on 24 isneutralized by the effect of 23 on 25 and the noises are practically cutentirely out.

In practice extraneous noises which under ordinary circumstances couldbe heard plainly with the receivers 27, 28 at arms length are thus socut out as to be low even with the receivers held closely to the ear,while the received signals are madesmore loud than when received direct.This is another striking difference between this apparatus and allprevious balanced circuits, for instead of the signals being weakenedthey are actually increased from five to ten times in loudness. Insteadof 12 for receiving the waves, an ordinary microphone may be used. Thismay be placed as usual .in a tank of water screwed to the ships side, ormay be attached as shown in Fig. 1, where 20 isa microphone of theinertia type attached by the clamp 19 to the wire 18, which may beadjustable in length if desired so as to tune to the received Waves. Bythrowing theswitch 17 down, the microphone 20 and battery 34 areconnected to the selective circuits above described, and the action isas described in the previous case, that is, the currents to be detectedpass over the tuned branch while the currents set up by the extraneousnoises divide between the two branches.

In Fig. 2, is a coppertube, say 8 inches diameter and 8 inches long (thelength being preferably equal to or less than the diameter). 45, is themagnetizing coil of the magnetic circuit, 4343 being north pole and 4444 being south pole. The magnetic flux flows from 4343 through the topair gap to the armature or core 41, thence through the bottom air gap to44-44 and back through the outside ring to 4343. The tube 40 lies in thetwo air gaps and such part of it as is not over the windings 46, 47, ispreferably slotted vertically as at ance. .Thewindings 46, 47 ,.arepreferably wound on the core 41, though they may. be wound on the insideofthe poles 4343, 44-44. In the drawings thesewindings are merely showndiagrammatically, but should preferably be about two hundred turns offlat steel enameled onto the core. It is best that the tube 40 shall bemovable rather 50, Fig. 2 or otherwise made'of high resistiss than thewindings as the tube is solid, though theoretically either might bemovable. 48, 49 are plates for bolting 4343 and 4444 and 41 together. 42is a hole for lifting, mounting terminals, etc. On passing an alternatincurrent of .a frequency of 1,000 throug 46, 47, the tube 40 acts asashort circuited secondary, and has induced in it the same number ofampere turns as 46, 47. Consequently, being inthe air gap which has, sayabout 11,000 lines per square centimeter, it is driven up and down witha force, in the apparatus described, of over 3,500 lbs. The stroke maybe of any desired length. If the side of a ship or the piston rod of alocomotive be attached to the ends of the tube 40, it will be set inmotion. This form of motor has the great advantage over all otheralternating current motors in that owing to the short-circuiting actionof 40 there is no hysteresis or inductance or eddy currents. At afrequency of 1,000 per second, and an ohmic resistance of 4 ohms for thewinda voltage of 87 volts will make 20 amperes pass through the circuit,showing a very high power factor, and this when the tube 40 is heldstill. When the tube is allowed to move the power factor is very closeto unity. The losses are very small, and the construction is very cheapper horse power, as no laminated iron need be used, and the winding isvery simple and the amount of wire very small. The starting torque isvery high. Two-phase current may be used, one phase on turns 46 and theother on turns 47. The two phases have one common point which isconnected to the point where 46 and 47 join. The force is very large perunit of current, and hence it is well adapted for submarine signaling.It is of altogether different dimensions to what has been obtainedheretofore, and if applied for one second would give a 12 inch shellthree time the velocity it has when fired from a 12 inch gun. It startsup very rapidly on account of the small time constant, 11. e., of aboutthe one ten thousandth of a second.

Fig. 3 shows another form where the device is used for a telephonereceiver. Here 60 is the telephone diaphragm, 61 is the tube, N S is themagnet, 62 being the armature or core and 63-63 the pole, circular inform, and 64 64 being the winding. On currents ings,

from a microphone passing through 64-64 the tube 61 vibrates and thediaphragm 60 to which it is attached reproduces the sound. In thisconstruction only one air gap is used. One reason for two air gaps inFig. 2 is that when used as a microphone by winding 46 in the oppositedirection to 47 they act dif-. ferently as regards any fluctuations inthe magnetizing coil 45, and give silence except for the receivedsignals. This is not necessary in Fig. 3 with a permanent magnet.

Also in Fig. 2 the tube 40 may be cut in two half way down, and bothends may be made to move oppositely, the windings 46, 47 being in thesame direction. This gives no unbalanced inertia efiects. By the use ofthis novel construction the obstacle which has prevented the use ofoscillating dynamos, 2'. 6., the dragging of the lines of force with themotion of the coil, is done away with. To such an extent is this truethat the device here shown is more sensitive, for equal motions, thanany carbon microphone. It will detect motions less than one per cent. ofthose which carbon microphone will detect. The absence of dragging oflines and of inductance and hysteresis makes it very suitable for tuninto which hysteresis is almost absolutely fatal. Such microphones may becoupled in series, or parallel,'which carbon microphones cannot be, onaccount of difference of phase. The device has many uses, which need notbe here enumerated. When used as a telephone relay, the tube ispreferably attached to a diaphragm having a higher natural period thanthe average frequency of the voice. This is to strengthen the highervibrations, which fall ofl most.

VVhat'I claim as my invention is:

1. The method of selecting and utilizing periodic impulses whichconsists in first transforming the energy of the impulses received intothe energy of fluctuating currents comprising periodic and non-periodicimpulses, impressing all the impulses bothperiodic and non-periodic upona circuit tuned to the periodic impulses to be detected and also upon acircuituntuned to any frequency within the range of said impulses andthereby neutralizing the effect on an indicating apparatus of oneportion of the nonperiodic impulses by the other portion thereof,whereby the indicating apparatus will be affected by the periodicimpulses.

2. The method of selecting and utilizing periodic impulses whichconsists in first transforming the energy of the impulses received intothe energy of fluctuating currents comprising periodic and non-periodicimpulses, impressing all the impulses both periodic and non-periodicupon a circuit tuned to the periodicimpulses to be detected and alsoupon a circuit untuned to any frequency within the range of saidimpulsesand thereby neutralizing the effect on an indicating apparatusof one portion of the nonperiodic impulses by the other portion thereof,whereby the indicating apparatus will be affected by the periodicimpulses, and maintaining the effect on the indicating apparatus of theperiodic impulses at'practically full strength.

3. The method of selecting and utilizing periodic impulses whichconsists in first transforming the energy of the impulses received intothe energy of fluctuating currents comprising periodic and non-periodicimpulses, impressing all the impulses both periodic and non-periodicupon a circuit' tuned to the periodic impulses to be detected and alsoupon a circuit untuned to any fre quency Within the range of saidimpulses and utilizing said fluctuating currents so separated toenergize a secondary circuit containing an indicating apparatus andneutralizing the effect of one portion of the nonperiodic impulses uponsaid secondary circuit by the other portion thereof, whereby theindicating apparatus Will be affected practically by the periodicimpulses only.

4. The method of selecting and utilizing periodic impulses whichconsists in first transforming the energy of the impulses received intothe energy of fluctuating currents comprising periodic and non-periodicimpulses, impressing all the impulses both periodic and non-periodicupon a circuit tuned to the periodic impulses to be detected and alsoupon a circuit untuned to any frequency Within the range of saidimpulses and utilizing said fluctuating currents so separated toenergize a secondary circuit containing an indicating apparatus andneutralizing the effect of one portion of the nonperiodic impulses uponsaid secondary circuit by the other portion thereof, whereby theindicating apparatus Will be affected practically by the periodicimpulses only,

and maintaining the effect on the indicating apparatus of said periodicimpulses at practically full strength.

5. The method of selecting periodic impulses by causing the impulsesreceived to excite fluctuating electric currents comprising periodic andnon-periodic impulses, impressing all the impulses both periodic andnon-periodic upon a circuit tuned to the periodic impulses to bedetached and also upon a circuit untuned to any frequency Within therange of said impulses and thereby neutralizing the efi'ect on anindicating apparatus of a portion of the non-periodic impulses by theother portion thereof Whereby the indicating apparatus will practicallynot be afiected thereby.

6. Apparatus for selecting periodic impulses fromimpulses of a pluralityof different frequencies, comprising means for transforming the energyof the received impulses into energy of fluctuating currents, a dividedcircuit for carrying such fluctuating currents, one side being tuned tothe impulses to be received, and the other side untuned to any of saidplurality of frequencies Within the range of said impulses, andreceiving apparatus connected to both sides of the divided circuit.

7. Apparatus for selecting periodic impulses from impulses of aplurality of different frequencies, comprising means for transformingthe energy of the received impulses into energy for fluctuatingcurrents, a divided circuit for carrying such fluctuating currents, oneside being tuned to the impulses to be received, and the other sideuntuned to any of said plurality of frequencies Within the range of saidimpulses, and receiving apparatus inductively connected to both sides ofthe divided circuit.

8. Apparatus for selecting periodic im pulses, comprising means fortransforming the energy of the received impulses into energy offluctuating currents, a divided primary for carrying said currents, oneside of the primary being tuned to the impulses to be received, adivided secondary inductively connected to both primaries, andoperatively connected to an electromagnetic indicating mechanism and thedivided primaries being placed in close relation so that they are ininductive relation to each other as Well as to their respectivesecondaries.

9. Apparatus for selecting periodic impulses, comprising means fortransforming the energy of the received impulses into energy offluctuating currents, a divided primary for carrying said currents, oneside of the primary being tuned to the impulses to be received, adivided secondary inductively connected to both primaries, andoperatively .connected to an electromagnetic indicating mechanism andthe divided primaries'being placed in close relation that they are ininductive relation to each other as well as to their respectivesecondaries, and in such fashion that their inductive effects opposeeach other.

v REGINALD A. FESSENDEN.

Witnesses:

GEORGE O. G. COSER, M. E. FLAHERTY.

